The invention relates to an electronic triggering device for a two-motor wiper system with two electric motors, in particular for a motor vehicle, and to a method for triggering such a triggering device.
Lately, so-called two-motor wiper systems have been used as windshield wiper systems for motor vehicles. Conventional wiper systems of this kind each have one electric motor for the drive on the driver's side and on the front passenger's side, preferably DC motors, and each of the electric motors is triggered by a separate control unit with a set of control electronics. Each set of control electronics includes an H bridge with power electronics switch elements, in particular power MOSFETs. Each of the H bridges includes a parallel circuit of two half bridges, and each of the half bridges has a series circuit of two switch elements. Thus a conventional set of control electronics has four switch elements for each motor of a two-motor wiper system. The power electronics for both motors together accordingly include a total of eight switch elements.
With these eight switch elements, it is possible to change the sign of the control voltage that drives the electric motors in terms of its polarity and thus to achieve a reversal of the direction of rotation of the motor. Moreover, with the aid of a selectable switching or clocking frequency for the switch elements, it is possible to regulate the effective magnitude of the supply voltage and thereby the rpm of the electric motors.